Telephone system



July 29, 1941. w. KUSCHE TELEPHONE SYSTEM Filed March 20, 1939 INVENTOR: WALTER KUSCHE 24 Z 31444 ATTORNEY.

' Patented July 29, 1941 TELEPHONE SYSTEM Application March 20, 1939, Serial No. 262,807

' In Germany March 31, 1933 10 Claims.

The invention relates to a circuit arrangement for party lines in remote signalling in particular telephone installations, and represents a further development of the arrangement in the German application S. 122,307.

In the main patent an arrangement is shown by which an effective control of impulse acceptors at the branch sets is made possible in a simple manner, in that switch means belonging to the branch sets disconnect the impulse accepting relays on the common line as soon as these have come into effect, on the receipt of an impulse sent out over the common line. This principle is used with special advantage in systems in which the control of the accepting relays is performed alternately by impulses in different directions. In such systems an eiiective control of the impulse accepting relay during the whole selecting impulse train is made possible in such a manner that the impulse accepting relays on the common line, at the branch sets, when they come into operation control switch means which put rectifiers in a circuit with the impulse accepting relays influenced by a current in one direction, so that further operation of the relays by current in this direction is prevented.

For this purpose two rectifiers are preferably provided at each branch set which pass in opposite directions and under the control of the switch means operated by the impulse accepting relay are alternatively connected in circuit with the impulse accepting relays. When polarized relays are used as accepting relays and are connected across the lines, these relays when they are operated by current in one direction (e. g. positive), are connected to rectifiers blocking current in this direction.

In systems in which the accepting relays at the branch sets are in series in the common line, use can also be made of the idea of the invention by connecting rectifiers with various operating directions parallel to the accepting relays, which rectifiers short circuit the polarized accepting relays for the passage of current in one direction after they come into eliect on the passage of current in this direction.

In the accompanying drawing an embodiment is shown to which however, the invention is not limited. In this embodiment only the details necessary for the understanding of the invention are shown and all the remaining known devices for talking and selecting are omitted.

In the embodiment a party line GL is shown to which several branch sets are connected. Of

these branch sets a sending station S and two'- receiving sets El and E2 are shown. The arrangement need not, however, always be such that at the branch sets either only sending or only receiving arrangements areprovided, but

both arrangements can be combined at each set.

The embodiment is selected in its-presentform' current producer which can also be shown as connected to one network however. The current supplied from this alternating current source'is used to select stations over the party line. The switch operations'are as follows: a

When one of the receiving setsEl or E2 is to be selected, then on the taking up of the receiver at the sending set S in the first place a circuit for the slow relay A is completed: earth, local battery 0B3,resistance Wil, relay A, switch hook contact'hu3, earth. The switch hook contacts hul' and huZ, which eifect the connection of the sending device at the party line, are so adjusted that they come into operation before the contacts al and A2 have left their normal positions. As a result an impulse is transmitted to the party line which can act as This impulse, which consistsa seizing impulse. of a half wave (e. g. positive) of the alternat ing current supplied by the alternating current source WQ, operates on the party line in the following manner: from the repeater Ue over the rectifier G2, impulse contact mi (in rest position), hook switch contact huZ, a-conductor of the party line and-then alongthe party line to the individual branch sets, e. g. to the branch set El over rectifier Gll, contact bl, polarized relay PI, and to branch set E2 over rectifier G2], contact b2, relay P2 etc. to the bconductor of the party line, contact hul, al,. to

the repeater Ue. The positive half wave of the alternating current therefore operatesv at all branch sets on the polarized relay P. The operation is now however in practice such that in view of the different current divisions on the line the polarized relay at the next sending sta-i tion is energized to the full in the first place and immediately operates, i. e. for example, therelay PI is operated and shifts its contact ,pl..

its operation position, so that'atthe receiving taking up of the receiver whose period is determined by the operating period of the slow relay A, includes a number of periods of the alternating current, an operation of the accepting relay lying most remote is effectively ensured." 'When the relay A finally comes to operate, the abovementioned circuit is interrupted by the opening of the contact al, while over the contact a2 a circuit is prepared for the release impulse.

If now the dial at the sending station is rotated, it closes the contact 'nsa; therefore a further half wave of positive direction is sent out, which however, since all polarized accepting relays are already in their operated positions, is without efiect. Only when the dial at the sending set has returned and the impulse contact psi at the sending set has reached its operated position for the first time, is the further transmission of half waves of positive direction stopped, since now in place of the rectifier G2 a rectifier with the opposite direction of operation (OH) is connected; 1. e. on the first closing of the impulse sending contact (nsz') impulses of negative direction are transmitted over the party line, which now control the polarized relays Pl, P2, etc. at the receiving sets over the rectifiers Gl2, G22, etc. open for current in the negative direction. The same operations are repeated as before. The relays which in view of favourable current ratios, come to operate immediately, set their contacts pl, p2, etc. to normal under the control of the current in the negative direction; thus, however, the relays BI, B2, etc. in the local circuits are disconnected, so that the contacts bi, 112, etc. also reach their normal positions and hence the polarized relays are again connected in series with the rectifiers GI l, GZI, etc. only open for current in the positive direction. Therefiore, in this case also all the relays are operated efiectively, since before the completion of the selecting impulse for the relay which is most difficult to operate in View of the disconnection of all the remaining. relays the complete energy -trans mitted stands at its disposal. On the further operation of the dial the operations already described are repeated until finally at the end of the dial selection in view of the setting back of the contact nsi to its normal position a current of. positive direction is sent as a last impulse to the party line; therefore the polarized relays Pl, P2, etc. are in their operating positions; and therefore at all branch sets the relays Bl, B2, etc. are also connected.

When at the end of the conversation the receiver is hung up at the sending station, then by the opening of the contact hu3 the relay A is disconnected, and in View of the parallel connected condenser K only restores slowly. Therefore over the contact hul in its normal position and hul and the contacts a! and a2 momentarily in their operated positions a circuit is completed for the current from the alternating current source WQ and this extends over the repeater Ue, rectifier GI, contact a2 hook switch contact huZ, a-conductor of the party line, rectifier G12, contact bl, relay PI, and rectifier =G2, contact b2, relay P2, etc. b-conductor of the party line, contacts hul, a2 to the repeater Ue. By this impulse of negative direction sent out over the line all the accepting relays are effectively set back to normal, as described, until the release of the relay A in the sending station.

As rectifiers at the branch sets known dry-plate rectifiers, lamps, or the like may be used. Since the polarized relays have high resistances, they cause very slight decrease in the speech in spite of their connection to the common line for the whole of the time.

In systems in which the receiving devices are not in bridge but in series with the company lines, it is also possible to make use of the idea of the invention. In order to obtain the same success in such cases with respect to the effective control of the accepting relays it is necessary to connect the rectifiers at the individual branch sets not in series with the polarized receiving relays but in parallel thereto, so that for example after the coming into efiect of the polarized relay on a current of positive direction this relay connects the rectifier of positive direction of operating over an auxiliary relay, so that the polarized relay is for the time being short circuited for current flowing in the positive direction. The total resistance is therefore reduced and in view of the corresponding current increase, an efiective operation of the remaining relays is made possible. On the following impulse in the opposite direction the same operations are repeated in such a manner that for current in the negative direction the relay which is not short-circuited is energized, its auxiliary relay is connected and then over the contact of the auxiliary relay in its normal position the short circuit for the current in this direction is brought about.

What is claimed is:

1. In a telephone system, a party line serving a plurality of stations, a station selecting relay at each station adapted to operate when energized and, when operated, to remain operated without continued energization, a connection from each relay to the line, a substantially uni-directional current blocking device at each station, means for operating said relays to select a station by connecting direct current of a certain polarity to said line to energize all of said relays, means individual to each relay and responsive to the operation thereof to interrupt said connection of that relay to the line and to connect the relay to said line through said device, said device thereafter preventing further energization of the associated relay by current of said certain polarity.

2. In combination, a line, two rectifiers, a. relay connected to said line through one of said rectifiers, means for. transmitting over said line current of the polarity to which said one rectifier is transparent thereby to energize said relay, means controlled by said relay responsive to the operation of same by said current for thereupon interrupting the connection oi said relay to the line through said one rectifier and connecting said relay to the line through the other of said rectifiers, said other rectifier thereafter effective, so long as said relay isconnected to the line therethrough, to prevent energization of said relay by current of the polarity to which said one rectifier was. transparent.

3. A combination: as claimed in claim 2, wherein said first means is effective at some time while said relay is connected to said line through said other rectifier to transmit over said line current .of the polarity to which said other rectifier is transparent, and wherein said second means is controlled by said relay responsive to the operation of same by current of the polarity to which said other rectifier is transparent'for thereupon interrupting the connection of said relay to the line'through said other rectifier and connecting said relay to the line through said one rectifier, said one rectifier thereafter effective, so 10ng as said relay remains connected to the line therethrough, to prevent energization of said relay by current of the polarity to which said other rectifier was transparent.

4. In combination, a line, a relay on said line normally responsive. only to the connection to said line of a potential of a certain polarity, means for connecting a potential of said certain polarity to said line to energize the relay, and means controlled by said relay thereupon to interrupt said energization and to condition the relay to respond only to the connection to said line of a potential of a different polarity.

5. In a combination as claimed in claim 4, means for connecting a potential of said different polarity to said line to energize said relay when same is conditioned to respond thereto, said means controlled by the relay effective thereupon to interrupt said last energization and to condition the relay to respond only to the connection 'to said line of a potential of said certain polarity.

6. In combination, a line, a plurality of relays connected to said line, a potential of a certain polarity, means for connecting said potential to said line to energize said relays, and means individual to and controlled by each relay upon its energization to interrupt, for so long as said potential remains connected to said line, the energization of that relay.

7. In combination, a relay of the type adapted to take different positions in response to the energization of its operating winding by current of different polarities and, when it has taken any position, to remain in that position until said operating winding is energized by current of a polarity different from that by which said relay was caused to take that position, means for energizing the operating winding of said relay by current of a polarity different from that by which said winding was last energized, thereby to cause said relay to take a new position, and means controlled by said relay responsive to said relay taking said new position for at once substantially blocking the flow through said operating winding of current of the polarity by which said relay was caused to take said new position, thereby to prevent said operating winding from being ener-;

gized substantially longer than is necessary to operate said relay to said new position.

'8. In combination, a relay of the type adapted to take different positions in response to the energizing the operating winding of said relay by current of a polarity different from that by which said winding was last energized, thereby to cause said relay to take a new position, a rectifier, and means controlled'by said relay responsive to said relay taking said new position for connecting said rectifier in series with said operating winding thereby to substantially block further energization of said operating winding by current of the polarity by which said relay was caused to take said new position, said rectifier permitting said operating winding to be energized only by current of a polarity different from that by which said relay was caused to take said new position.

9. In combination, a relay of the type which has no normal position and which will change from one position to another only when its operating winding is energized by current of a polarity different from that by which said winding was energized to operate said relay to said one posicion, means for energizing said winding by current of different polarities at different times to cause said relay to change position, said last means including means controlled by said relay in whatever position said relay then occupies for substantially preventing said winding from being energized by current of the same polarity asthat by which said winding was energized to operate said relay to said then occupied position.

10. In combination, a line, means for impressing upon said line current of different characters,

' a plurality of loads connected to said line and energized by current of one character when same is impressed upon said line, means individual to each load effective upon energization of that load by current of said one character to render that load opaque to current of said one character but to maintain said load connected to said line to permit energization thereof by current of another character.

WALTER. KUSCHE. 

